Improvements in the production of ethylene bis-thiuram monosulphide

Ethylene bis-thiuram monosulphide is prepared by reacting an aqueous solution containing at least 1 per cent w/v. of a di-alkyl metal or di-ammonium salt of ethylene bis-dithiocarbamic acid with oxygen or air in the presence of an oxidation catalyst at a temperature not greater than 40 DEG C., preferably 10-25 DEG C., while the solution is vigorously agitated. It is preferred to use di-sodium ethylene bis-dithiocarbamate as starting material but the di-potassium and di-ammonium salts may also be used. The concentration of the solution may be as high as is obtainable, but concentrations of 5-30 per cent w/v. are preferred. The preferred oxidation catalyst is manganese sulphate used in amounts of 5-10 gm. of sulphate per gm. mol. of starting material. The agitation of the reaction mixture may be effected by blowing oxygen through the solution. It is preferred to effect the reaction in a closed vessel into which oxygen is introduced under pressures of 2-50 p.s.i.g., the solution being pumped rapidly round a closed circuit including the reaction vessel and a cooler to remove the heat of reaction. Circulation rates of up to 700 changes per hour are suitable. A suitable form of such an apparatus is described. Detailed examples are given.